In a world first, detailed plans for an underground city have been presented in Helsinki. Over the next decade, planners aim to build 400 underground facilities with a total volume of 9 million cubic metres, which will add to existing infrastructure under the city’s central station that links it to a shopping centre almost a kilometre away.

One of the main features of this complex, the Stockmann department store, which is well-known throughout Europe, has just completed a major development programme to build an extra 10,000 m2 of retail space. So as to avoid traffic snarls, city authorities constructed a network of underground tunnels to facilitate the removal of bedrock and the transport of equipment to and from the work site.

And now this network will now be used as an underground supply circuit for the city, which will reduce traffic in Helsinki’s Old Town. Three ring roads to the north of the coastal city will also make extensive use of underground tunnels.

A building that could survive a nuclear attack

The next big investment dubbed Pisara, “the drop” in Finnish, will be an underground rail link on a drop-shaped route between the city’s suburbs and its central station. But that is not all. In three years, the central station will also benefit from a high-speed rail link to Vantaa airport (20km from the city centre) — yet another underground project that will pass under the airport’s runways.

Five years ago, Europe’s largest underground bus station was built in Helsinki, and the city’s main tourist attraction, Temppeliaukio Church, which attracts half a million tourists a year is, as you might expect, underground — not a temple on the mount, but a temple in the mount. With its solid rock walls the church has excellent acoustic properties, which is why is very often used for concerts.

Helsinki is also home to the European Chemicals Agency (ECHA), which manages procedures for the registering and monitoring of chemicals throughout the EU. The site for the ECHA headquarters was specifically chosen for its underlying bedrock which allowed for the construction of four underground levels for storage space and conference halls, which the custodians of the building proudly explain would even survive a nuclear attack.

Danes are building an 18km immersed tunnel

Ten kilometres from central Helsinki, the Itäkeskus centre is Europe’s largest underground shopping mall, which is also home to a swimming pool, an ice rink and numerous saunas, which are a feature of life in Finland.

But all of these marvels pale in comparison to a proposed 50km long undersea tunnel spanning the Gulf of Finland to provide road and rail links between Helsinki and the Estonian capital Tallinn. However, the project, which has the potential to boost development in the region and diminish the Finnish economy’s dependence on sea transport, is still awaiting a green light from governments in both countries.

In the Fehmarn strait at the other end of the Baltic, the Danes are building a 18km immersed tunnel. At a cost of 5 billion euros, the project which will connect the German offshore island of Fehmarn to the Danish island of Lolland, will create a fixed link between Zealand and Germany.

Wandering through the underground galleries

Most of the underground building in Sweden is concentrated in the city of Stockholm, where local citizens have not heard so many underground explosions since the inventor of dynamite, Alfred Nobel, sparked a revolution in the mining industry. Under Lake Malar, work is underway on a tunnel that will provide a new access route to the capital, skirt around the old town and come close to the foundations of Stockholm’s oldest church, which dates from the 13th century and houses the historic tombs of Sweden’s monarchs.

Further north, some of the most interesting underground investments in Sweden are to be found in Kiruna, which is famous for its iron deposits. Half a kilometre underground, the sight of the crowds strolling along the brightly lit pavements of the city’s mines is reminiscent of a busy street in Stockholm. Everyone is welcome to wander through the underground galleries, which are open around the clock, where they can observe the miners at work, and visit cafés and a museum.

Back on the surface, Kiruna has been condemned to a death sentence by the rich vein of iron ore that passes under the city. If this mineral wealth is to be exploited, the population will have to be moved. However, no seems to know exactly where they should go.

People vote with their feet and their wallets

The vogue for underground construction has also reached Norway, where authorities have been eager to build shortcuts on the country’s 25,000km long coastline. Among the many underground and undersea projects, at almost 25 kilometres long, the tunnel between Norway’s two major cities, Oslo and Bergen, is the longest road tunnel in the world.

Scandinavia is one of the least populated regions of Europe. Given that there should be plenty of room for eveyone, the recent vogue for underground building is in many ways baffling.

In the past, Scandinavians were enthusiastic builders of garden cities, a field in which they developed a high degree of mastery (for example the district of Tapiola, in Helsinki). But times have changed, and today they appear to more at home in more urban settings. Independently of what urban planners think, people vote with their feet and their wallets, and they are ready to pay astronomical sums to live in city centres. Given their traditional dislike of high buildings and skyscrapers, the only choice left for the Scandinavians is to dig underground.